The following notes come from an edited IRC session and the distribution used
was Ubuntu, package names and installation commands may differ in other distros.

Note that you may need a semi-recent distribution for the appropriate GTK3.2
libraries to be available. E.g. the below doesn't work on LinuxMint 18.3 or
earlier, though you may be able to manually download and compile GTK3.22 for
your platform (untested).

Tested on:  Linux Mint 19, Ubuntu 17.10.1, Ubuntu 18.04, Ubuntu 19.04,
    Debian 9.0-9.8, Debian 10.0, Debian 10.3

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1. adhoc build from SVN
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first, check out the svn:

if you dont have svn, install it first
$ sudo apt-get install subversion

$ mkdir myworkdir
$ cd myworkdir
$ svn checkout https://svn.code.sf.net/p/vice-emu/code/trunk trunk

now ... you will need some packages:
$ sudo apt-get install autoconf
$ sudo apt-get install automake
$ sudo apt-get install build-essential  # (contains gcc, make)
$ sudo apt-get install byacc
$ sudo apt-get install flex
$ sudo apt-get install xa65             # needed to build the vsid driver
$ sudo apt-get install libgtk-3-dev
$ sudo apt-get install texinfo
$ sudo apt-get install texlive-fonts-recommended
$ sudo apt-get install dos2unix         # only used when doing `make dist`
$ sudo apt-get install libpulse-dev     # for Pulse Audio sound support
$ sudo apt-get install libasound2-dev   # for ALSA sound support
$ sudo apt-get install libglew-dev      # for OpenGL hardware scaling support

The following are optional but recommended (not required for a basic build):

$ sudo apt-get install texi2html        # Doesn't appear to be required at all
                                        # since VICE carries its own texi2html
                                        # in doc/html (tested on Debian 10)
$ sudo apt-get install libreadline-dev
$ sudo apt-get install libgif-dev       # GIF screenshot support
$ sudo apt-get install libjpeg-dev      # JPEG screenshot support
$ sudo apt-get install libpcap-dev      # Ethernet support


If you have those installed, do run autogen.sh inside the vice dir:
$ cd trunk/vice/
$ ./autogen.sh
that should complete without error (and generate the actual configure scripts)

try configuring now:
$ ./configure --enable-native-gtk3ui
it should complete without error

lets try compiling it... we'll reconfigure again later and enable the options
you are missing :)
$ make

try running x64sc
$ ./src/x64sc

note: VICE expects ROM images at /usr/lib/vice, if you've not installed VICE
      before, these won't be present and x64sc will fail.
      In that case, tell x64sc where to find the ROM's:
      $ ./src/x64sc -kernal data/C64/kernal \
                    -basic data/C64/basic \
                    -chargen data/C64/chargen
      Once you've succesfully run `make install`, the ROMs will be present at
      $PREFIX/lib[64]/vice and the above command won't be necessary anymore.

success :)
$ sudo make install


NOTE: The following is from the previous Linux build readme and may not be
      relevant (I've updated most of this for Gtk3 now, I think --compyx)

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2. tweak the configuration
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run x64 in a terminal, it should print a line that tells some config details:

$ ./src/x64
<...>
*** VICE Version 3.3, rev 35869:35870 ***

Welcome to x64, the free portable C64 emulator.
<...>


install additional packages:

$ sudo apt-get install libpcap-dev        # for ethernet emulation

$ sudo apt-get install libavcodec-dev     # for video capturing support
$ sudo apt-get install libavformat-dev
$ sudo apt-get install libswscale-dev

$ sudo apt-get install libmp3lame-dev     # required for MP3 encoding
$ sudo apt-get install libmpg123-dev      # required for MP3 decoding (and for
                                          # mp3@64 cartridge support)
$ sudo apt-get install libogg-dev         # Ogg/Vorbis support
$ sudo apt-get install libflac-dev        # FLAC support

$ sudo apt-get install yasm               # required for --enable-static-ffmpeg
                                          # and --enable-shared-ffmpeg, yasm
                                          # needs to be >=1.2.0

reconfigure with a few more options (check if you really want/need them!):
$ ./configure --enable-arch=native --with-resid --enable-native-gtk3ui \
    --enable-ethernet --with-pulse --with-alsa --enable-cpuhistory \
    --enable-vte --enable-external-ffmpeg

(optionally add --enable-debug-gtk3ui --enable-debug to get debugging messages
 to better debug problems, or to help reporting bugs)


compile again...
$ make

... and finally install
$ sudo make install

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3. staying up to date
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Once you did all this, you can keep your local work directory, and build
yourself a cutting edge version simply by doing:

$ svn up
$ make
$ sudo make install

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4. For KDE users
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If opening the PDF doesn't work, you may have to register a KDE-based
application to handle opening the PDF:

In a normal-user shell, issue:

$ gio mime application/x-pdf org.kde.okular.desktop

This will register okular with GIO as the PDF handler.

Hopefully this is a temporary solution which we can fix by using xdg-open.